The present disclosure relates to a storage apparatus furnished with storage elements that store information using changes in the electrical characteristics of a storage layer, and to an operating method for operating such a storage apparatus.
Information devices such as computers utilize high-speed high-density DRAM's (dynamic random access memories) extensively. However, DRAM's are more costly to manufacture than typical logic circuit LSI's (large scale integrated circuits) and signal processing circuits commonly used in electronic devices. That is because producing DRAM's involves more complicated manufacturing processes than making the other circuits. Another disadvantage of the DRAM is that it is a volatile memory that loses the information stored therein when its power is removed. As such, the DRAM in operation needs to be refreshed frequently, i.e., to have the written information (data) read out therefrom, amplified again, and written back thereto repeatedly.
Meanwhile, recent years have witnessed the development of resistance change storage elements (nonvolatile memory). For example, “A Novel Resistance Memory with High Scalability and Nanosecond Switching,” by K. Aratani et al, Technical Digest IEDM 2007, pp. 783-786 (called the Non-Patent Document 1 hereunder) proposes a new type of resistance change storage elements that are particularly advantageous with regard to the limits of micro-fabrication of memory elements.
The reader may also refer to Japanese Patent Laid-Open Nos. 2003-187590 (called the Patent Document 1 hereunder), 2004-234707 (Patent Document 2), 2007-133930 (Patent Document 3), and 2010-198702 (Patent Document 4).